Gain Matching - need advice


I recently added an Audio Research Ref 6 to my system (it was a dealer demo unit so price was right).  The preamp is paired with Pass Labs XA 60.8 amps (26db gain and 100K ohm input impedance) and Avantgarde speakers (sensitivity of 108 db at nominal 8 ohms).  The problem I am having, that I did not have with my previous Joule Electra LA150, is volume control.  The AR preamp has a 103 position volume control.  At position #7 the volume is almost ear splitting.  Sure I can turn it down but it’s very difficult to dial in a suitable volume.  I am inclined to blame it on the new AR preamp (output impedance of 600 ohms and 12db of gain).  I am stuck into using balanced interconnects which I won’t go into.  My first conclusion was that I have a gain matching problem since the old preamp did not behave this way.  Looking at the difference between the output impedance of the preamp and input impedance of the preamp ... why would there be a gain matching problem (at least as I understand the subject ... which I may not.  Anything that can be done about this, or a new preamp the only solution?
chilli42

Showing 1 response by speakermaster

You do have a gain problem because of the having to use balanced interconnects it gives you 12 decibels more gain than what you think 6 db from the pre amp and amp each that would give you 32 plus 18 which is 50 db of gain way too much on an avantgarde if you could hook it up single ended you would have 38 db of gain ant that would be ok on the avangardes i would think but maybe still a little too much but nothing like the 50 db you have now.